Digital wrist watches, and especially the LED type, require the physical act of pressing a button, or other activating means, in order to cause the visual display of the time, date, month, as well as additional functions, carried out by known digital wrist watches. It is also well known that the requirement of depressing a button in order to exhibit the time display has caused a lack of acceptance by many potential purchasers of LED digital wrist watches. Therefore, it is evident that an LED wrist watch having a visual display activated automatically by the normal arm and wrist movement of a person viewing his watch would be of great significance in achieving mass acceptance of the LED digital wrist watch.
The present invention relates to LED digital wrist watches, and especially to a mercury switch arrangement which automatically actuates the watch display into one or more functions.
It is an object of the present invention to provide a non-wetting, curved sealed glass or Teflon tube having a mercury globule or bead therein. The mercury bead will constantly seek the lowest point in the tube due to the influences of gravity. Electrical contacts are so placed in a curved tube that when the wrist watch is held at a normal viewing angle, the mercury bead will move to a predetermined position in the curved tube whereby the electrical contacts are engaged, thus actuating the digital watch display.
It is another object of the present invention to fill the curved tube housing the mercury bead with a selected medium which is dependent upon the response time sought, such as vacuum or air for fast response, or oil, or other viscous medium, for slow response.
A further feature of the present invention is to provide an additional disabling switch for the digital watch display circuit so that the display will not be activated when the watch is not being worn, but is being carried, for example in a briefcase or a traveling bag. This fearture prevents an unwanted current drain of the digital watch battery when the watch is not being worn.
It is another object of the present invention to provide a curved tube of non-wetting metal, said tube accommodating a mercury bead and having the walls of the tube function as one of the electrical leads.
It is a further object of the present invention to provide a metal sphere or ball in a curved glass or thermoplastic tube, the latter being provided with spaced depressions with electrical contacts therein, whereby said metal sphere may roll by means of gravity into a selected depression and activate the digital display, depending upon the watch wearer's arm and wrist orientation.